Wang Jing, Gao Xueqin, Wang Xing, Song Wenxue, Wang Qin, Wang Xucheng, Li Shuxia, Fu Bingzhe
School of Agriculture, Ningxia University, Yinchuan, Ningxia, China.
Ningxia Grassland and Animal Husbandry Engineering Technology Research Center, Yinchuan, Ningxia, China.
Front Plant Sci. 2022 Dec 19;13:1051165. doi: 10.3389/fpls.2022.1051165. eCollection 2022.
Drought is one of the most common abiotic stressors in plants. Melatonin (MT) is a high-efficiency and low-toxicity growth regulator that plays an important role in plant responses to drought stress. As a wild relative of wheat, has become an important species for the improvement of degraded grasslands and the replanting of sandy grasslands. However, the physiological and molecular mechanisms by which exogenous MT regulates drought stress in remain unclear. To assess the effectiveness of MT intervention (100 mg·L), polyethylene glycol 6000 was used to simulate drought stress, and its ameliorating effects on drought stress in seedlings were investigated through physiology, transcriptomics, and metabolomics. Physiological analysis indicated that MT treatment increased the relative water content and chlorophyll content and decreased the relative conductivity of seedlings. Additionally, MT decreased malondialdehyde (MDA) and reactive oxygen species (ROS) accumulation by enhancing antioxidant enzyme activities. The transcriptome and metabolite profiling analysis of seedlings treated with and without MT under drought stress identified the presence of 13,466 differentially expressed genes (DEGs) and 271 differentially expressed metabolites (DEMs). The integrated analysis of transcriptomics and metabolomics showed that DEGs and DEMs participated in diverse biological processes, such as flavonoid biosynthesis and carbohydrate metabolism. Moreover, MT may be involved in regulating the correlation of DEGs and DEMs in flavonoid biosynthesis and carbohydrate metabolism during drought stress. In summary, this study revealed the physiological and molecular regulatory mechanisms of exogenous MT in alleviating drought stress in seedlings, and it provides a reference for the development and utilization of MT and the genetic improvement of drought tolerance in plants from arid habitats.
干旱是植物中最常见的非生物胁迫因素之一。褪黑素（MT）是一种高效低毒的生长调节剂，在植物应对干旱胁迫中发挥着重要作用。作为小麦的野生近缘种，已成为改良退化草原和沙地草原补种的重要物种。然而，外源MT调节其干旱胁迫的生理和分子机制尚不清楚。为评估MT干预（100 mg·L）的有效性，使用聚乙二醇6000模拟干旱胁迫，并通过生理学、转录组学和代谢组学研究其对该幼苗干旱胁迫的缓解作用。生理分析表明，MT处理提高了该幼苗的相对含水量和叶绿素含量，降低了相对电导率。此外，MT通过增强抗氧化酶活性降低了丙二醛（MDA）和活性氧（ROS）的积累。对干旱胁迫下经MT处理和未经MT处理的该幼苗进行转录组和代谢物谱分析，确定存在13466个差异表达基因（DEGs）和271个差异表达代谢物（DEMs）。转录组学和代谢组学的综合分析表明，DEGs和DEMs参与了多种生物学过程，如类黄酮生物合成和碳水化合物代谢。此外，MT可能参与调节干旱胁迫期间类黄酮生物合成和碳水化合物代谢中DEGs和DEMs的相关性。总之，本研究揭示了外源MT缓解该幼苗干旱胁迫的生理和分子调控机制，并为MT的开发利用以及干旱生境植物耐旱性的遗传改良提供了参考。
